/*
 *  pci_irq.c - ACPI PCI Interrupt Routing ($Revision: 11 $)
 *
 *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
 *  Copyright (C) 2002       Dominik Brodowski <devel@brodo.de>
 *  (c) Copyright 2008 Hewlett-Packard Development Company, L.P.
 *      Bjorn Helgaas <bjorn.helgaas@hp.com>
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or (at
 *  your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  General Public License for more details.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */


#include <linux/dmi.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/spinlock.h>
#include <linux/pm.h>
#include <linux/pci.h>
#include <linux/acpi.h>
#include <linux/slab.h>
#include <linux/interrupt.h>

#define PREFIX "ACPI: "

#define _COMPONENT              ACPI_PCI_COMPONENT
ACPI_MODULE_NAME("pci_irq");

struct acpi_prt_entry {
        struct acpi_pci_id      id;
        u8                      pin;
        acpi_handle             link;
        u32                     index;          /* GSI, or link _CRS index */
};

static inline char pin_name(int pin)
{
        return 'A' + pin - 1;
}

/* --------------------------------------------------------------------------
                         PCI IRQ Routing Table (PRT) Support
   -------------------------------------------------------------------------- */

/* http://bugzilla.kernel.org/show_bug.cgi?id=4773 */
static const struct dmi_system_id medion_md9580[] = {
        {
                .ident = "Medion MD9580-F laptop",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "MEDIONNB"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "A555"),
                },
        },
        { }
};

/* http://bugzilla.kernel.org/show_bug.cgi?id=5044 */
static const struct dmi_system_id dell_optiplex[] = {
        {
                .ident = "Dell Optiplex GX1",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex GX1 600S+"),
                },
        },
        { }
};

/* http://bugzilla.kernel.org/show_bug.cgi?id=10138 */
static const struct dmi_system_id hp_t5710[] = {
        {
                .ident = "HP t5710",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "hp t5000 series"),
                        DMI_MATCH(DMI_BOARD_NAME, "098Ch"),
                },
        },
        { }
};

struct prt_quirk {
        const struct dmi_system_id *system;
        unsigned int            segment;
        unsigned int            bus;
        unsigned int            device;
        unsigned char           pin;
        const char              *source;        /* according to BIOS */
        const char              *actual_source;
};

#define PCI_INTX_PIN(c)         (c - 'A' + 1)

/*
 * These systems have incorrect _PRT entries.  The BIOS claims the PCI
 * interrupt at the listed segment/bus/device/pin is connected to the first
 * link device, but it is actually connected to the second.
 */
static const struct prt_quirk prt_quirks[] = {
        { medion_md9580, 0, 0, 9, PCI_INTX_PIN('A'),
                "\\_SB_.PCI0.ISA_.LNKA",
                "\\_SB_.PCI0.ISA_.LNKB"},
        { dell_optiplex, 0, 0, 0xd, PCI_INTX_PIN('A'),
                "\\_SB_.LNKB",
                "\\_SB_.LNKA"},
        { hp_t5710, 0, 0, 1, PCI_INTX_PIN('A'),
                "\\_SB_.PCI0.LNK1",
                "\\_SB_.PCI0.LNK3"},
};

static void do_prt_fixups(struct acpi_prt_entry *entry,
                          struct acpi_pci_routing_table *prt)
{
        int i;
        const struct prt_quirk *quirk;

        for (i = 0; i < ARRAY_SIZE(prt_quirks); i++) {
                quirk = &prt_quirks[i];

                /* All current quirks involve link devices, not GSIs */
                if (dmi_check_system(quirk->system) &&
                    entry->id.segment == quirk->segment &&
                    entry->id.bus == quirk->bus &&
                    entry->id.device == quirk->device &&
                    entry->pin == quirk->pin &&
                    !strcmp(prt->source, quirk->source) &&
                    strlen(prt->source) >= strlen(quirk->actual_source)) {
                        printk(KERN_WARNING PREFIX "firmware reports "
                                "%04x:%02x:%02x PCI INT %c connected to %s; "
                                "changing to %s\n",
                                entry->id.segment, entry->id.bus,
                                entry->id.device, pin_name(entry->pin),
                                prt->source, quirk->actual_source);
                        strcpy(prt->source, quirk->actual_source);
                }
        }
}

static int acpi_pci_irq_check_entry(acpi_handle handle, struct pci_dev *dev,
                                  int pin, struct acpi_pci_routing_table *prt,
                                  struct acpi_prt_entry **entry_ptr)
{
        int segment = pci_domain_nr(dev->bus);
        int bus = dev->bus->number;
        int device = pci_ari_enabled(dev->bus) ? 0 : PCI_SLOT(dev->devfn);
        struct acpi_prt_entry *entry;

        if (((prt->address >> 16) & 0xffff) != device ||
            prt->pin + 1 != pin)
                return -ENODEV;

        entry = kzalloc(sizeof(struct acpi_prt_entry), GFP_KERNEL);
        if (!entry)
                return -ENOMEM;

        /*
         * Note that the _PRT uses 0=INTA, 1=INTB, etc, while PCI uses
         * 1=INTA, 2=INTB.  We use the PCI encoding throughout, so convert
         * it here.
         */
        entry->id.segment = segment;
        entry->id.bus = bus;
        entry->id.device = (prt->address >> 16) & 0xFFFF;
        entry->pin = prt->pin + 1;

        do_prt_fixups(entry, prt);

        entry->index = prt->source_index;

        /*
         * Type 1: Dynamic
         * ---------------
         * The 'source' field specifies the PCI interrupt link device used to
         * configure the IRQ assigned to this slot|dev|pin.  The 'source_index'
         * indicates which resource descriptor in the resource template (of
         * the link device) this interrupt is allocated from.
         * 
         * NOTE: Don't query the Link Device for IRQ information at this time
         *       because Link Device enumeration may not have occurred yet
         *       (e.g. exists somewhere 'below' this _PRT entry in the ACPI
         *       namespace).
         */
        if (prt->source[0])
                acpi_get_handle(handle, prt->source, &entry->link);

        /*
         * Type 2: Static
         * --------------
         * The 'source' field is NULL, and the 'source_index' field specifies
         * the IRQ value, which is hardwired to specific interrupt inputs on
         * the interrupt controller.
         */

        ACPI_DEBUG_PRINT_RAW((ACPI_DB_INFO,
                              "      %04x:%02x:%02x[%c] -> %s[%d]\n",
                              entry->id.segment, entry->id.bus,
                              entry->id.device, pin_name(entry->pin),
                              prt->source, entry->index));

        *entry_ptr = entry;

        return 0;
}

static int acpi_pci_irq_find_prt_entry(struct pci_dev *dev,
                          int pin, struct acpi_prt_entry **entry_ptr)
{
        acpi_status status;
        struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
        struct acpi_pci_routing_table *entry;
        acpi_handle handle = NULL;

        if (dev->bus->bridge)
                handle = ACPI_HANDLE(dev->bus->bridge);

        if (!handle)
                return -ENODEV;

        /* 'handle' is the _PRT's parent (root bridge or PCI-PCI bridge) */
        status = acpi_get_irq_routing_table(handle, &buffer);
        if (ACPI_FAILURE(status)) {
                kfree(buffer.pointer);
                return -ENODEV;
        }

        entry = buffer.pointer;
        while (entry && (entry->length > 0)) {
                if (!acpi_pci_irq_check_entry(handle, dev, pin,
                                                 entry, entry_ptr))
                        break;
                entry = (struct acpi_pci_routing_table *)
                    ((unsigned long)entry + entry->length);
        }

        kfree(buffer.pointer);
        return 0;
}

/* --------------------------------------------------------------------------
                          PCI Interrupt Routing Support
   -------------------------------------------------------------------------- */
#ifdef CONFIG_X86_IO_APIC
extern int noioapicquirk;
extern int noioapicreroute;

static int bridge_has_boot_interrupt_variant(struct pci_bus *bus)
{
        struct pci_bus *bus_it;

        for (bus_it = bus ; bus_it ; bus_it = bus_it->parent) {
                if (!bus_it->self)
                        return 0;
                if (bus_it->self->irq_reroute_variant)
                        return bus_it->self->irq_reroute_variant;
        }
        return 0;
}

/*
 * Some chipsets (e.g. Intel 6700PXH) generate a legacy INTx when the IRQ
 * entry in the chipset's IO-APIC is masked (as, e.g. the RT kernel does
 * during interrupt handling). When this INTx generation cannot be disabled,
 * we reroute these interrupts to their legacy equivalent to get rid of
 * spurious interrupts.
 */
static int acpi_reroute_boot_interrupt(struct pci_dev *dev,
                                       struct acpi_prt_entry *entry)
{
        if (noioapicquirk || noioapicreroute) {
                return 0;
        } else {
                switch (bridge_has_boot_interrupt_variant(dev->bus)) {
                case 0:
                        /* no rerouting necessary */
                        return 0;
                case INTEL_IRQ_REROUTE_VARIANT:
                        /*
                         * Remap according to INTx routing table in 6700PXH
                         * specs, intel order number 302628-002, section
                         * 2.15.2. Other chipsets (80332, ...) have the same
                         * mapping and are handled here as well.
                         */
                        dev_info(&dev->dev, "PCI IRQ %d -> rerouted to legacy "
                                 "IRQ %d\n", entry->index,
                                 (entry->index % 4) + 16);
                        entry->index = (entry->index % 4) + 16;
                        return 1;
                default:
                        dev_warn(&dev->dev, "Cannot reroute IRQ %d to legacy "
                                 "IRQ: unknown mapping\n", entry->index);
                        return -1;
                }
        }
}
#endif /* CONFIG_X86_IO_APIC */

static struct acpi_prt_entry *acpi_pci_irq_lookup(struct pci_dev *dev, int pin)
{
        struct acpi_prt_entry *entry = NULL;
        struct pci_dev *bridge;
        u8 bridge_pin, orig_pin = pin;
        int ret;

        ret = acpi_pci_irq_find_prt_entry(dev, pin, &entry);
        if (!ret && entry) {
#ifdef CONFIG_X86_IO_APIC
                acpi_reroute_boot_interrupt(dev, entry);
#endif /* CONFIG_X86_IO_APIC */
                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %s[%c] _PRT entry\n",
                                  pci_name(dev), pin_name(pin)));
                return entry;
        }

        /*
         * Attempt to derive an IRQ for this device from a parent bridge's
         * PCI interrupt routing entry (eg. yenta bridge and add-in card bridge).
         */
        bridge = dev->bus->self;
        while (bridge) {
                pin = pci_swizzle_interrupt_pin(dev, pin);

                if ((bridge->class >> 8) == PCI_CLASS_BRIDGE_CARDBUS) {
                        /* PC card has the same IRQ as its cardbridge */
                        bridge_pin = bridge->pin;
                        if (!bridge_pin) {
                                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                                  "No interrupt pin configured for device %s\n",
                                                  pci_name(bridge)));
                                return NULL;
                        }
                        pin = bridge_pin;
                }

                ret = acpi_pci_irq_find_prt_entry(bridge, pin, &entry);
                if (!ret && entry) {
                        ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                         "Derived GSI for %s INT %c from %s\n",
                                         pci_name(dev), pin_name(orig_pin),
                                         pci_name(bridge)));
                        return entry;
                }

                dev = bridge;
                bridge = dev->bus->self;
        }

        dev_warn(&dev->dev, "can't derive routing for PCI INT %c\n",
                 pin_name(orig_pin));
        return NULL;
}

#if IS_ENABLED(CONFIG_ISA) || IS_ENABLED(CONFIG_EISA)
static int acpi_isa_register_gsi(struct pci_dev *dev)
{
        u32 dev_gsi;

        /* Interrupt Line values above 0xF are forbidden */
        if (dev->irq > 0 && (dev->irq <= 0xF) &&
            acpi_isa_irq_available(dev->irq) &&
            (acpi_isa_irq_to_gsi(dev->irq, &dev_gsi) == 0)) {
                dev_warn(&dev->dev, "PCI INT %c: no GSI - using ISA IRQ %d\n",
                         pin_name(dev->pin), dev->irq);
                acpi_register_gsi(&dev->dev, dev_gsi,
                                  ACPI_LEVEL_SENSITIVE,
                                  ACPI_ACTIVE_LOW);
                return 0;
        }
        return -EINVAL;
}
#else
static inline int acpi_isa_register_gsi(struct pci_dev *dev)
{
        return -ENODEV;
}
#endif

static inline bool acpi_pci_irq_valid(struct pci_dev *dev, u8 pin)
{
#ifdef CONFIG_X86
        /*
         * On x86 irq line 0xff means "unknown" or "no connection"
         * (PCI 3.0, Section 6.2.4, footnote on page 223).
         */
        if (dev->irq == 0xff) {
                dev->irq = IRQ_NOTCONNECTED;
                dev_warn(&dev->dev, "PCI INT %c: not connected\n",
                         pin_name(pin));
                return false;
        }
#endif
        return true;
}

int acpi_pci_irq_enable(struct pci_dev *dev)
{
        struct acpi_prt_entry *entry;
        int gsi;
        u8 pin;
        int triggering = ACPI_LEVEL_SENSITIVE;
        /*
         * On ARM systems with the GIC interrupt model, level interrupts
         * are always polarity high by specification; PCI legacy
         * IRQs lines are inverted before reaching the interrupt
         * controller and must therefore be considered active high
         * as default.
         */
        int polarity = acpi_irq_model == ACPI_IRQ_MODEL_GIC ?
                                      ACPI_ACTIVE_HIGH : ACPI_ACTIVE_LOW;
        char *link = NULL;
        char link_desc[16];
        int rc;

        pin = dev->pin;
        if (!pin) {
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                  "No interrupt pin configured for device %s\n",
                                  pci_name(dev)));
                return 0;
        }

        if (dev->irq_managed && dev->irq > 0)
                return 0;

        entry = acpi_pci_irq_lookup(dev, pin);
        if (!entry) {
                /*
                 * IDE legacy mode controller IRQs are magic. Why do compat
                 * extensions always make such a nasty mess.
                 */
                if (dev->class >> 8 == PCI_CLASS_STORAGE_IDE &&
                                (dev->class & 0x05) == 0)
                        return 0;
        }

        if (entry) {
                if (entry->link)
                        gsi = acpi_pci_link_allocate_irq(entry->link,
                                                         entry->index,
                                                         &triggering, &polarity,
                                                         &link);
                else
                        gsi = entry->index;
        } else
                gsi = -1;

        if (gsi < 0) {
                /*
                 * No IRQ known to the ACPI subsystem - maybe the BIOS /
                 * driver reported one, then use it. Exit in any case.
                 */
                if (!acpi_pci_irq_valid(dev, pin))
                        return 0;

                if (acpi_isa_register_gsi(dev))
                        dev_warn(&dev->dev, "PCI INT %c: no GSI\n",
                                 pin_name(pin));

                kfree(entry);
                return 0;
        }

        rc = acpi_register_gsi(&dev->dev, gsi, triggering, polarity);
        if (rc < 0) {
                dev_warn(&dev->dev, "PCI INT %c: failed to register GSI\n",
                         pin_name(pin));
                kfree(entry);
                return rc;
        }
        dev->irq = rc;
        dev->irq_managed = 1;

        if (link)
                snprintf(link_desc, sizeof(link_desc), " -> Link[%s]", link);
        else
                link_desc[0] = '\0';

        dev_dbg(&dev->dev, "PCI INT %c%s -> GSI %u (%s, %s) -> IRQ %d\n",
                pin_name(pin), link_desc, gsi,
                (triggering == ACPI_LEVEL_SENSITIVE) ? "level" : "edge",
                (polarity == ACPI_ACTIVE_LOW) ? "low" : "high", dev->irq);

        kfree(entry);
        return 0;
}

void acpi_pci_irq_disable(struct pci_dev *dev)
{
        struct acpi_prt_entry *entry;
        int gsi;
        u8 pin;

        pin = dev->pin;
        if (!pin || !dev->irq_managed || dev->irq <= 0)
                return;

        /* Keep IOAPIC pin configuration when suspending */
        if (dev->dev.power.is_prepared)
                return;
#ifdef  CONFIG_PM
        if (dev->dev.power.runtime_status == RPM_SUSPENDING)
                return;
#endif

        entry = acpi_pci_irq_lookup(dev, pin);
        if (!entry)
                return;

        if (entry->link)
                gsi = acpi_pci_link_free_irq(entry->link);
        else
                gsi = entry->index;

        kfree(entry);

        /*
         * TBD: It might be worth clearing dev->irq by magic constant
         * (e.g. PCI_UNDEFINED_IRQ).
         */

        dev_dbg(&dev->dev, "PCI INT %c disabled\n", pin_name(pin));
        if (gsi >= 0) {
                acpi_unregister_gsi(gsi);
                dev->irq_managed = 0;
        }
}